1. Field
Example embodiments relate to semiconductor devices and methods of manufacturing the same, and more particularly, to high electron mobility transistors (HEMTs) and methods of manufacturing the same.
2. Description of the Related Art
Field effect semiconductor devices, for example, high electron mobility transistors (HEMTs), are electronic devices that may be used in high frequency bands. For example, HEMTs may be used in communication technologies operating at high frequencies.
A HEMT may include a hetero-junction structure including semiconductor material layers of different band gaps contacting each other. A semiconductor material layer with a relatively large band gap functions as a donor. A 2-dimensional electron gas (2DEG) may be induced in a semiconductor material layer with a relatively small band gap by the donor. Electrons may move faster within the 2-DEG of the junction than within planar semiconductor devices including a single semiconductor.
A HEMT is used to achieve increased mobility of electron carriers, and also as a power device, for example, a transistor with a high breakdown voltage. A HEMT includes a semiconductor with a wide band gap, for example, a compound semiconductor, and may break down at a relatively high breakdown voltage. Therefore, a HEMT may be used in high voltage applications.
Silicon, which is a common material widely used in a semiconductor device, has a relatively low electron mobility, and thus a high source resistance may occur. A group III-V compound semiconductor may be used in a HEMT instead of silicon. For example, a gallium nitride-based compound may be a material used in a HEMT due to a relatively wide band gap, high electron saturation velocity, and high chemical stability. HEMTs that use gallium nitride-based compounds may be high temperature, high power and high frequency electronic devices.